scholarly journals Emerging Technologies for Genome-Wide Profiling of DNA Breakage

2021 ◽  
Vol 11 ◽  
Author(s):  
Matthew J. Rybin ◽  
Melina Ramic ◽  
Natalie R. Ricciardi ◽  
Philipp Kapranov ◽  
Claes Wahlestedt ◽  
...  
Keyword(s):  
Genome Instability ◽  
Dna Double Strand Breaks ◽  
Single Nucleotide ◽  
Strand Breaks ◽  
Single Strand Breaks ◽  
Genome Wide ◽  
A Genome ◽  
Wide Scale ◽  
Nucleotide Resolution ◽  
Genomic Regions

Genome instability is associated with myriad human diseases and is a well-known feature of both cancer and neurodegenerative disease. Until recently, the ability to assess DNA damage—the principal driver of genome instability—was limited to relatively imprecise methods or restricted to studying predefined genomic regions. Recently, new techniques for detecting DNA double strand breaks (DSBs) and single strand breaks (SSBs) with next-generation sequencing on a genome-wide scale with single nucleotide resolution have emerged. With these new tools, efforts are underway to define the “breakome” in normal aging and disease. Here, we compare the relative strengths and weaknesses of these technologies and their potential application to studying neurodegenerative diseases.

scholarly journals MRE11-RAD50-NBS1 promotes Fanconi Anemia R-loop suppression at transcription–replication conflicts

2019 ◽  
Vol 10 (1) ◽  
Author(s):  
Emily Yun-Chia Chang ◽  
Shuhe Tsai ◽  
Maria J. Aristizabal ◽  
James P. Wells ◽  
Yan Coulombe ◽  
...  
Keyword(s):  
Dna Replication ◽  
Fanconi Anemia ◽  
Genome Instability ◽  
Double Strand Breaks ◽  
Dna Double Strand Breaks ◽  
Strand Breaks ◽  
Mrn Complex ◽  
Genome Wide ◽  
A Genome ◽  
Dna Replication Stress

Abstract Ectopic R-loop accumulation causes DNA replication stress and genome instability. To avoid these outcomes, cells possess a range of anti-R-loop mechanisms, including RNaseH that degrades the RNA moiety in R-loops. To comprehensively identify anti-R-loop mechanisms, we performed a genome-wide trigenic interaction screen in yeast lacking RNH1 and RNH201. We identified >100 genes critical for fitness in the absence of RNaseH, which were enriched for DNA replication fork maintenance factors including the MRE11-RAD50-NBS1 (MRN) complex. While MRN has been shown to promote R-loops at DNA double-strand breaks, we show that it suppresses R-loops and associated DNA damage at transcription–replication conflicts. This occurs through a non-nucleolytic function of MRE11 that is important for R-loop suppression by the Fanconi Anemia pathway. This work establishes a novel role for MRE11-RAD50-NBS1 in directing tolerance mechanisms at transcription–replication conflicts.

scholarly journals CNCC: An analysis tool to determine genome-wide DNA break end structure at single-nucleotide resolution

2019 ◽  
Author(s):  
Karol Szlachta ◽  
Heather M Raimer ◽  
Laurey D. Comeau ◽  
Yuh-Hwa Wang
Keyword(s):  
Topoisomerase Ii ◽  
Genome Instability ◽  
Analysis Tool ◽  
Single Nucleotide ◽  
Genome Wide ◽  
A Genome ◽  
Cross Correlation Analysis ◽  
Dna Break ◽  
Nucleotide Resolution ◽  
Single Nucleotide Resolution

AbstractDNA double-stranded breaks (DSBs) are potentially deleterious events in a cell. The end structures (blunt, 3’- and 5’-overhangs) at sites of double-stranded breaks contribute to the fate of their repair and provide critical information for consequences of the damage. Here, we describe the use of a coverage-normalized cross correlation analysis (CNCC) to process high-precision genome-wide break mapping data, and determine genome-wide break end structure distributions at single-nucleotide resolution. For the first time, on a genome-wide scale, our analysis revealed the increase in the 5’ to 3’ end resection following etoposide treatment, and the global progression of the resection due to the removal of DNA topoisomerase II cleavage complexes. Further, our method distinguished the change in the pattern of DSB end structure with increasing doses of the drug. The ability of this method to determine DNA break end structures withouta prioriknowledge of break sequences or genomic position should have broad applications in understanding genome instability.

scholarly journals CRISPR-BEST: a highly efficient DSB-free base editor for filamentous actinomycetes

2019 ◽  
Author(s):  
Yaojun Tong ◽  
Helene L. Robertsen ◽  
Kai Blin ◽  
Andreas K. Klitgaard ◽  
Tilmann Weber ◽  
...  
Keyword(s):  
Genome Instability ◽  
Cytidine Deaminase ◽  
Double Strand Breaks ◽  
Antimicrobial Compounds ◽  
Dna Double Strand Breaks ◽  
Single Nucleotide ◽  
Strand Breaks ◽  
Genetic Manipulations ◽  
Nucleotide Resolution ◽  
Single Nucleotide Resolution

AbstractFilamentous actinomycetes serve as major producers of various natural products including antimicrobial compounds. Although CRISPR-Cas9 systems have been developed for more robust genetic manipulations, concerns of genome instability caused by the DNA double-strand breaks (DSB) and the toxicity of Cas9 remain. To overcome these limitations, here we report development of the DSB-free, single-nucleotide resolution genome editing system CRISPR-BEST (CRISPR-Base Editing SysTem). Specifically targeted by an sgRNA, the cytidine deaminase component of CRISPR-BEST efficiently converts C:G to T:A within a window of approximately seven-nucleotides. The system was validated and successfully used in different Streptomyces species.

scholarly journals A nucleotide resolution map of Top2-linked DNA breaks in the yeast and human genome

2019 ◽  
Vol 10 (1) ◽  
Author(s):  
William H. Gittens ◽  
Dominic J. Johnson ◽  
Rachal M. Allison ◽  
Tim J. Cooper ◽  
Holly Thomas ◽  
...  
Keyword(s):  
Dna Cleavage ◽  
Genome Stability ◽  
Dna Double Strand Breaks ◽  
Dna Breaks ◽  
Strand Breaks ◽  
Single Strand Breaks ◽  
Human Genomes ◽  
Nucleotide Resolution

Abstract DNA topoisomerases are required to resolve DNA topological stress. Despite this essential role, abortive topoisomerase activity generates aberrant protein-linked DNA breaks, jeopardising genome stability. Here, to understand the genomic distribution and mechanisms underpinning topoisomerase-induced DNA breaks, we map Top2 DNA cleavage with strand-specific nucleotide resolution across the S. cerevisiae and human genomes—and use the meiotic Spo11 protein to validate the broad applicability of this method to explore the role of diverse topoisomerase family members. Our data characterises Mre11-dependent repair in yeast and defines two strikingly different fractions of Top2 activity in humans: tightly localised CTCF-proximal, and broadly distributed transcription-proximal, the latter correlated with gene length and expression. Moreover, single nucleotide accuracy reveals the influence primary DNA sequence has upon Top2 cleavage—distinguishing sites likely to form canonical DNA double-strand breaks (DSBs) from those predisposed to form strand-biased DNA single-strand breaks (SSBs) induced by etoposide (VP16) in vivo.

scholarly journals CNCC: an analysis tool to determine genome-wide DNA break end structure at single-nucleotide resolution

BMC Genomics ◽  
2020 ◽  
Vol 21 (1) ◽  
Author(s):  
Karol Szlachta ◽  
Heather M. Raimer ◽  
Laurey D. Comeau ◽  
Yuh-Hwa Wang
Keyword(s):  
Mapping Technique ◽  
Nucleotide Position ◽  
Analysis Tool ◽  
Single Nucleotide ◽  
Genome Wide ◽  
A Genome ◽  
Cross Correlation Analysis ◽  
Dna Break ◽  
Nucleotide Resolution ◽  
Single Nucleotide Resolution

Abstract Background DNA double-stranded breaks (DSBs) are potentially deleterious events in a cell. The end structures (blunt, 3′- and 5′-overhangs) at DSB sites contribute to the fate of their repair and provide critical information concerning the consequences of the damage. Therefore, there has been a recent eruption of DNA break mapping and sequencing methods that aim to map at single-nucleotide resolution where breaks are generated genome-wide. These methods provide high resolution data for the location of DSBs, which can encode the type of end-structure present at these breaks. However, genome-wide analysis of the resulting end structures has not been investigated following these sequencing methods. Results To address this analysis gap, we develop the use of a coverage-normalized cross correlation analysis (CNCC) to process the high-precision genome-wide break mapping data, and determine genome-wide break end structure distributions at single-nucleotide resolution. We take advantage of the single-nucleotide position and the knowledge of strandness from every mapped break to analyze the relative shifts between positive and negative strand encoded break nucleotides. By applying CNCC we can identify the most abundant end structures captured by a break mapping technique, and further can make comparisons between different samples and treatments. We validate our analysis with restriction enzyme digestions of genomic DNA and establish the sensitivity of the analysis using end structures that only exist as a minor fraction of total breaks. Finally, we demonstrate the versatility of our analysis by applying CNCC to the breaks resulting after treatment with etoposide and study the variety of resulting end structures. Conclusion For the first time, on a genome-wide scale, our analysis revealed the increase in the 5′ to 3′ end resection following etoposide treatment, and the global progression of the resection. Furthermore, our method distinguished the change in the pattern of DSB end structure with increasing doses of the drug. The ability of this method to determine DNA break end structures without a priori knowledge of break sequences or genomic position should have broad applications in understanding genome instability.

scholarly journals Novel approach reveals genomic landscapes of single-strand DNA breaks with nucleotide resolution in human cells

2019 ◽  
Vol 10 (1) ◽  
Author(s):  
Huifen Cao ◽  
Lorena Salazar-García ◽  
Fan Gao ◽  
Thor Wahlestedt ◽  
Chun-Lin Wu ◽  
...  
Keyword(s):  
Regulatory Elements ◽  
Single Strand ◽  
Dna Breaks ◽  
Strand Breaks ◽  
Template Strand ◽  
Naturally Occurring ◽  
Single Strand Breaks ◽  
Novel Approach ◽  
Genome Wide ◽  
Nucleotide Resolution

AbstractSingle-strand breaks (SSBs) represent the major form of DNA damage, yet techniques to map these lesions genome-wide with nucleotide-level precision are limited. Here, we present a method, termed SSiNGLe, and demonstrate its utility to explore the distribution and dynamic changes in genome-wide SSBs in response to different biological and environmental stimuli. We validate SSiNGLe using two very distinct sequencing techniques and apply it to derive global profiles of SSBs in different biological states. Strikingly, we show that patterns of SSBs in the genome are non-random, specific to different biological states, enriched in regulatory elements, exons, introns, specific types of repeats and exhibit differential preference for the template strand between exons and introns. Furthermore, we show that breaks likely contribute to naturally occurring sequence variants. Finally, we demonstrate strong links between SSB patterns and age. Overall, SSiNGLe provides access to unexplored realms of cellular biology, not obtainable with current approaches.

scholarly journals ANKRD31 regulates spatiotemporal patterning of meiotic recombination initiation and ensures recombination between heterologous sex chromosomes in mice

2018 ◽  
Author(s):  
Frantzeskos Papanikos ◽  
Julie A.J. Clément ◽  
Erika Testa ◽  
Ramya Ravindranathan ◽  
Corinne Grey ◽  
...  
Keyword(s):  
Sex Chromosomes ◽  
Meiotic Recombination ◽  
Meiotic Chromosome ◽  
Dna Double Strand Breaks ◽  
Strand Breaks ◽  
Homologous Chromosomes ◽  
Y Chromosomes ◽  
Genome Wide ◽  
A Genome ◽  
Pseudoautosomal Regions

AbstractOrderly segregation of chromosomes during meiosis requires that crossovers form between homologous chromosomes by recombination. Programmed DNA double-strand breaks (DSBs) initiate meiotic recombination. We identify ANKRD31 as a critical component of complexes of DSB-promoting proteins which assemble on meiotic chromosome axes. Genome-wide, ANKRD31 deficiency causes delayed recombination initiation. In addition, loss of ANKRD31 alters DSB distribution owing to reduced selectivity for sites that normally attract DSBs. Strikingly, ANKRD31 deficiency also abolishes uniquely high rates of recombination that normally characterize pseudoautosomal regions (PARs) of X and Y chromosomes. Consequently, sex chromosomes do not form crossovers leading to chromosome segregation failure in ANKRD31-deficient spermatocytes. These defects are accompanied by a genome-wide delay in assembling DSB-promoting proteins on axes and a loss of a specialized PAR-axis domain that is highly enriched for DSB-promoting proteins. Thus, we propose a model for spatiotemporal patterning of recombination by ANKRD31-dependent control of axis-associated complexes of DSB-promoting proteins.

scholarly journals Cannabis labelling is associated with genetic variation in terpene synthase genes

Nature Plants ◽  
2021 ◽  
Vol 7 (10) ◽  
pp. 1330-1334
Author(s):  
Sophie Watts ◽  
Michel McElroy ◽  
Zoë Migicovsky ◽  
Hugo Maassen ◽  
Robin van Velzen ◽  
...  
Keyword(s):  
Genetic Variation ◽  
Single Nucleotide Polymorphisms ◽  
Terpene Synthase ◽  
Nucleotide Polymorphisms ◽  
Single Nucleotide ◽  
Genome Wide ◽  
A Genome ◽  
Wide Scale ◽  
Tandem Arrays

AbstractAnalysis of over 100 Cannabis samples quantified for terpene and cannabinoid content and genotyped for over 100,000 single nucleotide polymorphisms indicated that Sativa- and Indica-labelled samples were genetically indistinct on a genome-wide scale. Instead, we found that Cannabis labelling was associated with variation in a small number of terpenes whose concentrations are controlled by genetic variation at tandem arrays of terpene synthase genes.

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